/* Copyright (C) 2000 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

/* Dynamic hashing of record with different key-length */

#ifndef _hash_h
#define _hash_h
#ifdef __cplusplus
extern "C"
{
#endif

/*
  Overhead to store an element in hash
  Can be used to approximate memory consumption for a hash
 */
#define HASH_OVERHEAD (sizeof(char *) * 2)

  typedef byte *(*hash_get_key)(const byte *, uint *, my_bool);
  typedef void (*hash_free_key)(void *);

  typedef struct st_hash
  {
    uint key_offset, key_length; /* Length of key if const length */
    uint records, blength, current_record;
    uint flags;
    DYNAMIC_ARRAY array; /* Place for hash_keys */
    hash_get_key get_key;
    void (*free)(void *);
    CHARSET_INFO *charset;
  } HASH;

#define hash_init(A, B, C, D, E, F, G, H) _hash_init(A, B, C, D, E, F, G, H CALLER_INFO)
  my_bool _hash_init(HASH *hash, CHARSET_INFO *charset, uint default_array_elements, uint key_offset, uint key_length,
                     hash_get_key get_key, void (*free_element)(void *), uint flags CALLER_INFO_PROTO);
  void hash_free(HASH *tree);
  void my_hash_reset(HASH *hash);
  byte *hash_element(HASH *hash, uint idx);
  gptr hash_search(HASH *info, const byte *key, uint length);
  gptr hash_next(HASH *info, const byte *key, uint length);
  my_bool my_hash_insert(HASH *info, const byte *data);
  my_bool hash_delete(HASH *hash, byte *record);
  my_bool hash_update(HASH *hash, byte *record, byte *old_key, uint old_key_length);
  void hash_replace(HASH *hash, uint idx, byte *new_row);
  my_bool hash_check(HASH *hash); /* Only in debug library */

#define hash_clear(H) bzero((char *)(H), sizeof(*(H)))
#define hash_inited(H) ((H)->array.buffer != 0)

#ifdef __cplusplus
}
#endif
#endif
